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Microaneurysm Turnover Predicts Retinopathy Progression

Dec 14, 2012
Automated analysis of microaneurysm (MA) turnover predicted the development of clinically significant macular edema (CSME) among patients with mild nonproliferative diabetic retinopathy (MNDR)….

Maria Luisa Ribeiro, MD, from the Association for Innovation and Biomedical Research on Light and Image and the Faculty of Medicine, University of Coimbra, Portugal, and colleagues report their findings in an article published online November 30 in Diabetes Care.

"The most important message is that MA turnover, obtained in an automated fashion from fundus digital photographs, which is a simple noninvasive test, can identify the eyes/patients at risk of developing CSME, the most frequent cause of vision loss due to diabetes," corresponding author José Cunha-Vaz, MD, PhD, said.


Dr. Cunha-Vas, emeritus professor of ophthalmology, University Hospital and University of Coimbra, and president of the Association for Innovation and Biomedical Research on Light and Image and the Faculty of Medicine, PhD, added that, "Patients with nonproliferative retinopathy and repeatedly showing little disease activity (low [MA] turnover) may need less frequent eye care."

In this prospective observational study, the investigators used the RetmarkerDR (Critical Health SA) diagnostic system to measure the rates of MA appearances and disappearances from color fundus photographs. This dynamic measure, which reflects both the closing down of MA because of thrombosis and the appearance of new aneurysms in different locations in the vascular tree, was shown in a previous study by the authors to predict worsening of retinopathy to CSME.

In the current study, the investigators evaluated MA turnover in 410 patients (1 eye each) with type 2 diabetes who at baseline had MNDR. They were evaluated at baseline, at 6 months and then again either at 2 years or at the time of development of CSME requiring laser photocoagulation (study endpoint).

Of the 410 patients enrolled, 348 (84.9%) patients either developed CSME or were examined at 2 years. Of those, 26 (7.5%) developed CSME during the 2-year period and received laser treatment.

The negative predictive value, 95.9%, demonstrated that "a low MA turnover value is associated with less likelihood for CSME development in a 2-year period," the authors write.

A higher hemoglobin A1c value was the only other significant predictor of progression to CSME among the other parameters analyzed (P = .022).

Dr. Cunha-Vaz added that, the RetmarkerDR could be used to annually screen patients to identify those at higher risk who might need closer monitoring. "By promptly identifying the eyes/patients at risk for vision-threatening complications, it is possible to treat earlier — as soon as the complication develops. These cases will respond better to therapy, thus avoiding late treatment associated with more complex and expensive therapies."

In addition, "It is expected…this tool will create a more efficient information flow between screeners, primary care physicians, diabetologists, and ophthalmologists, [ensuring] earlier and timely referrals."

The RetmarkerDR is not currently available in the United States, but Critical Health plans to pursue the US market, according to Dr. Cunha-Vaz.

Medscape Medical News, Diabetes Care Abstract